How is it implemented in Laravel?

Question

Laravel

If you create a route like this:

Route::get('product/{id}', '[email protected]');

Then in the controller the parameter should be exactly $id and nothing else:

...
public function index(Product $id)  {
    //$id - продукт
}

That is, you cannot designate a variable as {id} in the route, and accept $product in the controller.
I'm wondering how it's implemented? How to check the names of incoming parameters in php?

Answer 1

This is called reflection. Example:

$class = new \ReflectionClass('Название класса');  // Создаем объект для рефлексии класса
$method = $class->getMethod('Имя метода');   // Получаем метод по имени
$params = $method->getParameters();   // Получаем массив с параметрами
$paramName = $params[0]->getName();   // Берем первый элемент массива, он имеет тип ReflectionParameter, и получаем его имя.

You can immediately create an object to reflect the method "directly":

$method = new \ReflectionMethod('Класс', 'Имя метода');
// Далее, аналогично

With the help of reflection, you can not only get the names of parameters, but also their types, default values. You can even get dock blocks for methods/properties and so on. With the help of reflection, for example, doctrine orm works. It uses annotations (as one of the configuration options) to describe entities.